Are disappearing butterflies ag's problem?

Sunday, October 5, 2014

Agriculture has been implicated as the biggest cause of monarch decline. But farmers are questioning whether it is reasonable for them to bear the cost of remedial action

by DANA SNELL

A recent study by Tyler Flockhart, a post-doctoral researcher at the University of Guelph who specializes in migratory animals, is the latest to implicate agriculture in the dwindling population of the iconic monarch butterfly. His paper, published in the June online issue of the Journal of Animal Ecology, suggests that changing agricultural practices have a far greater impact on monarch numbers than any other factor.

This is the first study to look at all three major threats to monarchs concurrently, says Flockhart. Those factors are destruction of overwintering habitat in Mexico due to deforestation, severe weather events and the loss of breeding grounds (milkweed, which is the only plant the monarch lays eggs on) due to the adoption of genetically modified crops.

The theoretical model, which incorporates decades of previous data, found that the reduction of breeding habitat was four times more damaging to monarch numbers than the loss of overwintering habitat. As for severe weather events, under his model, the mitigating effect of climate change actually predicted a reduction in monarch deaths.

Flockhart is well aware that his findings point the finger at farmers, and he finds this "really unfortunate, because farmers are doing what they need to do to stay competitive and to run a business." And while he sees planting milkweed and managing roadsides where milkweed grows as a short-term solution, the only way to make a real impact on monarch numbers is for farmers to change their practices to some degree. "The question is, how can those changes be made so that they have the least impact on farmers and food production?"

But before such theoretical changes can be discussed, there must be consensus among the farming community that agriculture should even be asked to play a part. Gord Surgeoner, the outgoing president of Ontario Agri-Food Technologies, says placing the onus on farmers to save the monarch is "disrespectful of agriculture."

He thinks farmers, who are under pressure to produce more food for a growing population using fewer acres of farmland, have enough to worry about without taking on the fate of an insect. "Yes, we should create more habitats. The question is: who should pay for that? Should it be the farmer? Should it be society at large? Why are we saying that the farmer has to have more milkweeds in the plants and get reduced yields?"

Carol Pasternak, author of How to Raise Monarch Butterflies, agrees that the issue is a minefield. "I have clients who are farmers and you can't touch the subject at all. I can understand why they get very angry."

David Armitage, manager of the farm policy research group at the Ontario Federation of Agriculture, considers milkweed control and the attendant decline in monarch population an "unintended consequence" of farming. "The vast majority of farmers are proud of the native species that reside in bush and wetlands on their property. However, those same species are not welcome in their fields if they affect agricultural productivity."

Armitage sums up the disconnect between conservationists and farmers nicely: "Farmers are in the business of farming. Those not engaged in the business of farming often view farmland as a type of natural habitat. That is the problem . . . Commercial farming needs to be recognized as an industry and farm fields as sites of industrial activity."

At this point, the bulk of the milkweed loss is occurring in the central United States, a casualty of America's ethanol mandate that has seen Conservation Reserve Program lands converted to cornfields. But, since butterflies migrate such a great distance, every stop on the way is important. Ontario is vital because Ontario hosts two generations in a season and then they fly to Mexico to overwinter. "It's in Ontario where the numbers increase," Pasternak says. "So whatever role we can play in rebuilding the population, we have to do it . . . we can't just sit back and think, 'oh yeah, we have milkweed here. We're OK.' We've got to be vigilant."

Mike Cowbrough, weed management lead at the Ontario Ministry of Agriculture, Food and Rural Affairs, thinks there is quite a bit of milkweed on the edges of farmers' fields in Ontario, but can't quantify it because there has never been a formal count. "To be blunt," says Cowbrough, "there's currently no resources available to do it." He thinks that knowing the actual milkweed numbers would create a much more strategic approach than aimlessly planting. "We often get emotional about species, whether they're invasive species or beneficial species. Surveys would take a little bit of that emotion out of it and get a bit more quantitative about it."

One important benefit of Flockhart's study is the creation of a model that may take some of the daunting guesswork out of monarch conservation by assessing the effectiveness of different approaches – for example, managing milkweed in roadsides. Perhaps this may achieve some of the quantitative analysis Cowbrough is hoping for.

Meanwhile, many people have taken it upon themselves to plant milkweed in their gardens to provide monarch way stations. "You go to the nurseries," Pasternak says, "and they can't keep (milkweed) in stock." Also, some crop protection companies like Syngenta are investing in pollinator habitats.

Whether efforts like these will be enough to offset what Flockhart's study calculates as 1.5 billion milkweed plants removed over the past 20 years, the vast majority from farm fields, remains to be seen.

When contacted for this story, Farm and Food Care Ontario referred Better Farming to Grain Farmers of Ontario. There was no response to written questions in time for this publication.

No one responded to repeated telephone messages left with the Ontario Soil and Crop Improvement Association. BF